Fallout Community Edition, re-implementation of Fallout, with the same original gameplay, engine bugfixes, and some quality of life improvements. Works on multiple platforms.
The original Fallout is one of the great gaming experiences I have ever had. Fallout 2 was great and fixed a lot of the problems the first one had but the first one was something very special when it was fresh. It had the greatest user guide of all time. I have never seen a better guide. It stands on its own and the two together are part of what made it just so iconic.